Indoor unit shows CH06 and may stop cooling or heating.

Safety: Shut off power to the outdoor unit at the disconnect or breaker before opening the cabinet.

Steps:

• Open outdoor unit: Remove the service panel to access the control board and sensor wiring.
• Locate outdoor air thermistor: It is typically mounted near the outdoor coil or on the front grille area, sensing ambient air temperature.
• Inspect sensor and mount: Ensure the sensor is intact, not broken, and firmly attached in the airflow. Replace any broken mounting clips.
• Check wiring: Follow the sensor leads back to the PCB. Look for UV damage, rodent chewing, or pulled wires. Reseat the connector.
• Measure resistance: With a multimeter, check the thermistor resistance. An open or shorted reading indicates a failed sensor.
• Replace if faulty: Install a new LG outdoor air thermistor, routing the wires neatly and securing them away from sharp edges and the fan.
• Reassemble and test: Refit the panel, restore power, and operate the system to confirm CH06 is cleared.

Technician involvement: If the sensor and wiring are good but CH06 persists, the outdoor PCB may be defective and should be replaced by a professional.